<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>爱心</title>
    <style>
        body {
            height: 100vh;
            display: flex;
            justify-content: center;
            align-items: center;
        }

        .love {
            position: relative;
            width: 200px;
            height: 200px;
            background-color: red;
            transform: rotate(45deg);
            animation: love 1s linear infinite;

        }

        .love::after,
        .love::before {
            position: absolute;
            content: "";
            height: 200px;
            width: 200px;
            background-color: red;
            border-radius: 50%;

            animation: love 1s linear infinite;

        }

        .love::after {

            left: -100px;
        }

        .love::before {
            top: -100px;
        }

        @keyframes love {

            0%,
            100% {
                width: 200px;
                height: 200px;
            }

            20% {
                width: 230px;
                height: 230px;
            }
        }
    </style>
</head>

<body>
    <div class="love"></div>
</body>

</html>